**3.1 Physicochemical properties of OMW**

The physicochemical characteristics of OMW obtained from an extraction unit by the traditional press process are presented in **Table 1**. The effluents are reddishblack in color and darken during storage (**Figure 2**); they have a cloudy appearance and a strong odor of olive oil. It is an acidic liquid (pH = 4.90) with an electrical conductivity of 13.5mS/cm which is characteristic of wastewater. The contents of solid matter, chemical oxygen demand (COD) and biological oxygen demand (BOD5) weigh 40, 160 and 90 g/L of OMW, respectively, they are high. Crude proteins represent approximately 1% of the composition of vegetable waters; while


#### **Table 1.**

*Physicochemical properties of OMW collected from a traditional processing unit in Sefrou region (GAE: gallic acid equivalent).*

*Valorization of Olive Mill Wastewater in the Control of* Aphis pomi *De Geer 1773… DOI: http://dx.doi.org/10.5772/intechopen.100016*

potassium, calcium, sodium and magnesium represent from 1 to 0.05% of the total (**Table 1**). The samples of vegetable water analyzed are relatively rich in inorganic ions (P, Mn, Cu, Fe, Zn, Ni, Cd), their contents vary from approximately 642 to 0.015 mg/Kg. Sulfates, ammonium, nitrates, nitrites, chlorine and orthophosphate

#### **Figure 3.**

*Mortality of the different stages of* Aphis pomi *treated with crude OMW (SE: standard error; T +: imidacloprid; the bars with the same letter do not differ statistically from each other, ANOVA2F followed by the Tukey HSD test at 5%).*

are also dissolved in vegetable waters, their concentrations ranging between approximately 1592 and 12 mg/L; while the total polyphenol content is around 66 mg /L of OMW (**Table 1**).
